<header >
  <div class="container">
    <div class="logo">
      <img src="../../../assets/images/logo2.png" alt="migu-music" />
      <h1>Angular</h1>
    </div>
    <div class="user">
      <a *ngIf="user else context">请登录</a>
      <ng-template #context>
        张三<a>退出</a>
      </ng-template>
    </div>
  </div>
</header>
